In a rotation machine, wherein a rotation angle of its rotating body is detected and rotating position of the rotating body is controlled, for instance, in an inner diameter measuring device for measuring an inner diameter by rotating a probe, it is necessary to detect a rotation angle to specify measuring position of the probe, and also, an origin point for measuring the rotation angle is needed. Further, for the purpose of measuring inner diameter over total circumference, rotation amount of at least 360° is needed. Also, for the purpose of supplying electric power to the probe or of giving and taking the measurement result of the probe (electronic signal), cables or the like are to be connected to the probe. To prevent the cutting-off caused by twisting of cables or the like, it is necessary to restrict the rotation.
For this reason, in a rotation restricting device for the rotation machine, a function to detect the origin point must be provided, and also, a function to allow rotation of 360° or more to the rotating body and to restrict rotation more than an angle as predetermined are needed.
As a stopper for allowing rotation of 360° or more, a stopper disclosed in the Patent Document 1 is known. According to the Patent Document 1, there are provided a first circular plate where grooves are formed and a second circular plate having such projections as to be slidably engaged in the grooves. In the grooves as described above, two circular grooves where the centers deviated from each other are connected. A rotating body stopper is disclosed, by which it is possible to rotate for an angle of 360° or more as the projections are striding over from the first circular groove to the second circular groove.
To solve the problems as described above, it is an object of the present invention to provide a rotation restricting device for rotation machine, by which it is possible to restrict the rotation of a rotating body at a rotation angle exceeding 360°.